Blood Cells Parameters in Second Trimester of Pregnancy and Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis.

Objective: Gestational diabetes mellitus (GDM) is one of the most common complications during pregnancy. There is inconsistency between previous studies regarding the blood and inflammatory parameters levels among pregnant women and its association with GDM. This study aimed to investigate the relationship between blood parameters in relation to GDM.

Methods: Systematic literature searches were carried out through databases like PubMed, Web of Science, Epistemonikos, Scopus, Scientific Information Database and Magiran till May 2024. The effect size of serum blood parameters levels was determined by using standard mean deviations (SMDs) and 95% confidence intervals (CIs).

Results: Thirty articles were included in this study. Meta-analysis showed that compared with the control group, women with GDM had significantly higher levels of haemoglobin (0.343 [95% CI 0.134-0.553] p = 0.01, sensitivity analysis: 0.174 [95% CI 0.0343-0.315] p = 0.01), red blood cell (0.387 [95% CI 0.224-0.550] p < 0.001), mean platelet volume (0.498 [95% CI 0.165-0.831] p = 0.003), white blood cell count (0.351 [95% CI 0.0882-0.615] p = 0.009) and neutrophil-lymphocyte ratio (0.534 [95% CI 0.127-0.941] p = 0.01). However, women with GDM had lower levels of mean corpuscular haemoglobin concentration (-0.249 [95% CI -0.386--0.112] p < 0.001). Pooled results from MPV showed no association between adjusted MPV and GDM (adjusted OR 1.33 [95% CI 0.8-1.86] I = 57.2%).

Conclusions: Finding supports higher levels of blood parameters (Hb, RBC, WBC, NLR and MPV) among women with GDM in the second trimester of pregnancy. Future studies should investigate the potential role of these haematological markers as predictive tools for adverse pregnancy outcomes and evaluate therapeutic interventions targeting these parameters to enhance maternal and fetal health.